Various kinds of cartridge magazines have been proposed or devised for different firearms or weapons. These magazines include differently configured follower assemblies, which are used to support and move the cartridges in the magazine between a bottom end and a top end thereof. In the case of the conventional magazine for housing nine millimeter cartridges, the follower assembly includes a compression spring. When in its fully compressed state with the magazine full of cartridges, the compression spring occupies a certain amount of space. A cartridge magazine that discloses the use of a compression spring as part of the follower is disclosed in U.S. Pat No. 2,620,582 to Stukas, issued Dec. 9, 1952, and entitled "Firearm Magazine." Because of the space occupied by the compression spring when compressed, relatively fewer cartridges can be loaded for containment in such a conventional magazine. The present invention involves the use of a negator or spirally wound conforce spring as part of the follower assembly. Because of the spirally wound conforce spring, an essentially conventional-in-length body of a magazine, preferably a nine millimeter magazine, is able to house two more rounds or bullets than can be housed using the conventional follower assembly that includes a compression spring.
A spirally wound conforce spring has been used as part of the follower assembly in certain magazines. U.S. Pat. No. 4,509,283 to Chesnut, issued Apr. 9, 1985, and entitled "Cartridge Clip," as well as patents cited therein, discloses the use of a spirally wound conforce spring. The spring unwinds along an end wall of the magazine and adjacent to the rim ends of the cartridges. A spirally wound spring provided in a cartridge magazine is also disclosed in Belgium Pat. No. 635,534, issued Nov. 18, 1963. From the patent drawings, there is no rib formed in the magazine. Consequently, there is no means for preventing contact between the unwound spring portion and the cartridges. And there is, therefore, no space or gap continuously maintained between all of the cartridges and the unwound spring portion. This magazine also houses only a single column of cartridges. A magazine for housing a double column of cartridges with ribs formed in the side walls of the magazine is disclosed in U.S. Pat. No. 3,087,270 to Stoner, issued Apr. 30, 1963, and entitled "Ammunition Magazine With a Coil Spring." However, the ribs are not located to prevent contact between cartridges and unwound spring portion; rather, the ribs engage the nose ends of the cartridges to keep them in some desired alignment. Additionally, there is only a single layer of conforce spring centered, not offset, relative to the follower body. With regard to disclosures relating to the use of a single magazine with a plurality of differently styled but related firearms, U.S. Pat. No. 4,586,281 to Chesnut, issued Mar. 8, 1985, and entitled "Cartridge Magazine For Use With A Plurality Of Firearms" describes a magazine with a number of different latch-related elements.
Although it is known to incorporate a spirally wound conforce spring in a cartridge magazine as part of the follower assembly, such prior art is not concerned with identifying and solving the problems that were presented in arriving at the present invention. In order to provide a properly functioning magazine, it is important to properly locate or position the spirally wound conforce spring in the conventional-in-length body of the nine millimeter magazine. In that regard, it was necessary to identify where the spring could be located relative to the body and the follower, as well as providing, in at least some embodiments, a nesting area or pocket for the unwound portion of the spring. The selected spring location assists in providing a desired "nose up" condition for the cartridges while the nesting area prevents frictional engagement between the spring and the magazine body. In addition, the use of the spirally wound conforce spring resulted in the cartridges contained in the body of the magazine being relatively loose, which caused unwanted small amounts of movement or rattling noises, and this problem is solved by an embodiment of the present invention. Also, a sufficiently strong conforce spring configuration had to be devised and implemented because of the problem encountered in moving cartridges with a single conforce spring. Furthermore, the latch areas of the present inventive magazine had to be determined and incorporated so that the magazine could be used in different firearms.